Using the following representation of the Whittaker functions [1]}
\(\mathrm {M}_{\kappa ,\mu }\left( t\right) =t^{\mu +1/2}\sum _{n=0}^{\infty }\,_{2}F_{1}\left( \left.\begin{array}{c}-n,\mu -\kappa +\frac{1}{2} \\1+2\mu \end{array}\right|2\right) \frac{\left( -t/2\right) ^{n}}{n!},\) 
